1. Field of the Invention
The subject of the invention relates generally to microwave circuits such as phase shifters and more particularly to ones mounted on a cylindrical support.
2. Description of the Prior Art
Prior art microwave phase shifters are on linear boards and are mounted in a box where metal elements provide structural support.
Also in the prior art, there are several nonplanar printed circuits such as that shown in U.S. Pat. No. 2,611,040, Brunetti, which prints a circuit around a cylindrical electron tube. Similar U.S. Pat. Nos. are 2,720,578, Caffiaux et al. and 2,772,380, Andrew.
U.S. Pat. No. 3,080,541, Parker, shows a printed circuit coil structure which may be mounted on a cone or cylinder with support by a metallic base member. U.S. Pat. No. 3,755,891, Muckelroy et al., illustrates a three-dimensional circuit module for thick film circuits involving both printing inside and outside the walls of a hollow cylindrical substrate formed of a dielectric coating on a cylindrical housing.
U.S. Pat. No. 4,399,488, Ruwe et al., involves the packaging of microelectronics using a series of various size cylinders assembled and sealed from the environment with connections out opposite ends of the cylinders.
U.S. Pat. No. 4,412,272, Wedertz et al., shows a flexible printed circuit board with components mounted thereon which may be rolled into a spiral. U.S. Pat. No. 4,510,551, Brainard, discloses a memory module constructed in a compact cylindrical form with individual integrated circuit memory components interconnected by a flexible printed circuit which is rolled and inserted in a protective outer casing, also cylindrical. U.S. Pat. No. 4,528,748, Eichelberger et al., discloses a method for batch fabricating flat printed circuit boards and subsequently forming them to a particular shape such as a hexagon cylinder.
The above art does not disclose the use of a dielectric cylinder for structural support, nor a microwave application.